Spring for biasing a rocker arm



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MflQ/ON LEE TZIOMPSON United States Patent Office 3,139,872 Patented July 7, 1964 3,139,872 SPRING FOR BIASING A ROCKER ARM Marion Lee Thompson, 2734 Eastvale, Rolling Hills, Calif. Filed July 23, 1962, Ser. No. 211,630 3 Claims. (Cl. 123-90) 7 This invention relates to components of internal combustion engines, and more particularly to a spring employed to exert a torque on a rocker arm to cause the latter to follow closely the movements of a reciprocal push rod, and a clamp for supporting said spring.

An object of .this invention is to provide a spring which is employed to exert a torque on the rocker arm of an internal combustion engine in such a manner as to cause the rocker arm to follow closely the movements of a reciprocal rocker arm push rod, particularly the move ment of the push rod away from the rocker arm.

Another object of this invention is to provide a spring of the character described wherein the spring may be firmly anchored in place in a conventional internal combustion engine without requiring modification of the engine, and the space occupied by the spring will be no greater than the space presently available.

A yet further object of the invention is to provide a spring-of the character described wherein the force exerted by the spring on the rocker arm will not impair the operation of the push rod.

A still further object of this invention is to provide a spring of the character described wherein, when the spring is anchored in place, it is rendered non-pivotal and resistant to being displaced by re-occurring shocks and vibrations that emanate from an operating engine.

A more specific object of this invention is to provide a spring and clamp assembly for a rocker arm of the character described wherein the spring is releasably secured to theclamp about which the rocker arm pivots, and the spring, being nonpivotal, applies a torque to the rocker arm to cause the rocker arm to follow closely the movements of a reciprocal push rod.

These and other objects and advantages of the invention will become more apparent from a consideration of the description which follows, taken in conjunction with the drawings, in which:

FIGURE 1 is a fragmentary, sectional view illustrating a portion of an internal combustion engine having embodied therein one form of the present invention;

FIGURE 2 is an enlarged plan view taken on line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary, sectional view taken on line 3-3 of FIGURE 2;

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE .3;

FIGURE 5 is an exploded, perspective view illustrating one form of the spring of the present invention in association with a rocker arm, a fragment of a push rod, and structure for anchoring the spring;

FIGURE 6 is a plan view similar to FIGURE 2, but illustrating a second form of the present invention;

FIGURE 7 is a sectional view taken on line 7-7 of FIGURE 6; and

FIGURE 8 is a perspective view of the second form of the present invention.

Referring initially to the form of the invention illustrated in FIGURES 1-5, and particularly to FIGURE 5, there may best be seen a perspective view of a rocker arm spring 10. Embodied in the rocker arm spring 10 is a pair of spaced apart, torque producing coils 12 and 14, which are in substantial axial alignment with each other. Each of the coils 12 and 14 has irregular-shaped, cantilevered, internal extensions or legs 16 and 18, respectively, and external extensions or legs 20 and 22, respectively.

The internal legs 16 and 18 are in substantial parallel relationship with each other, and each of said legs 16 and 18 is foreshortened and rendered relatively rigid by slightly downwardly directed bends 24 and 26, respectively. Subjacent each bend 24 and 26 are relatively straight sections 28 and 30, respectively, which terminate in slightly upwardly directed bends 32 and 34, respectively. Projecting from each bend 32 and 34 are other relatively straight sections 36 and 38, respectively. Connecting said sections 36 and 38, and forming a substantially right angle with each last identified section, is a rocker arm yoke 40.

The external legs 20 and 22 are in substantial parallel relationship with each other, and each of said legs 20 and 22 includes a terminal end which is preferably formed into substantially semi-circular, axially aligned clamp loops 42 and 44, respectively, which embody straight channel fingers 46 and 48, respectively. Channel fingers 46 and 48 extend back toward their respective legs to substantially close the respective loop, and each channel finger forms substantially a right angle with the respective external leg. The axis of the loops 42 and 44 lies in substantially the same vertical plane as the axis of coils 12 and 14.

Legs 16 and 18, which extend generally in the same direction as channel fingers 46 and 48, each forms substantially an acute angle, with the single plane passing through the axis of the coils and loops; and with the legs 16 and 18 in this position when the spring 10 is properly installed, the legs exert a continual, downwardly directed bias, in a manner to be hereinafter described. Legs 20 and 22 are substantially parallel to the single plane passing through the axis of the coils and loops, and legs 20 and 22 serve preferably to support the coils in a generally upright position within a chamber 47, defined by an enclosing cup 49 (see FIGURE 1).

Each clamp loop 42 and 44 embraces the normally lower semi-cylindrical portion '50 of a substantially cylindrical split shaft 52. The channel fingers 46 and 48 are each received in a respective channel 54 and 56 disposed in portion 50, and the normally upper semi-cylindrical portion 58 of split shaft 52 is firmly applied over the fingers (see particularly FIGURES 2, 3 and 4). Firm application of portion 58 over fingers 46 and 48, and securely clamping the fingers between the two portions 50 and 58 of split shaft 52, is achieved by a stud 60 which passes through centrally located openings 61 and 63 in portions 50 and 58, respectively, and stud 60 threadably mates with a nut 62. Stud 60 is mounted in engine housing 65 (see FIGURE 3). Clamping of the fingers 46 and 48 between portions 50 and 58 serves to render the spring 10 captive and non-pivotal. Semi-cylindrical portion 58 of the split shaft 52 may have a diameter less than the diameter of portion 50 to permit assembling the split shaft 52 within a rocker arm 64 in a manner to be hereinafter described.

Split shaft 52 is employed as an axis about which rocker arm 64 pivots, and assembly of split shaft 52 within rocker arm 64 is preferably achieved by inserting the portions 50 and 58 through a pair of axially aligned bores 66 and 68, the walls of which provide bearing surfaces which are pivotal about portion 50. The actual securing of spring 10 to split shaft 52 is accomplished with the split shaft positioned in rocker arm 64.

When spring 10 is secured to split shaft 52, with legs 16 and 18 positioned on each side of rocker arm 64 (see FIGURE 4), coils 12 and 14 are positioned over rocker arm 64. The coils 12 and 14 are loaded to transmit a torque through the legs 16 and 18 to yoke 40 by positioning yoke 40 so that it bears down on a push rod projection 70, which is integral with the rocker arm 64. In this way yoke 40 imposes direct, downwardly exerted torque on push rod projection 70, represented by the torque arrow, best seen in FIGURE 3.

The operation of the form of invention illustrated in FIGURES 1-5 is as follows: a rotatable cam shaft 72, disposed in the engine housing 65, lifts a push rod cup 74, which in turn lifts a push rod 76. The uppermost end of push rod 76 seats in a cavity 78 (see FIGURE 3), located on the underside of push rod projection 70. The lifting of push rod 76 causes rocker arm 64 to pivot clockwise about shaft 52, as viewed in FIGURE 1, in opposition to the force imposed on the rocker arm by spring 10. Rocker arm 64 has an anvil 80 thereon which bears against a valve stem 82, and the pivoting of rocker arm 64 results in opening the valve 84 (see FIGURES 1 and 3), and admitting fuel into a combustion chamber where it is compressed by a reciprocal piston 86 and ignited by a spark plug 87 (see'FIGURE 1).

When cam shaft 72 is in the position illustrated in FIGURE 1, following admission of fuel into the engine combustion chamber, push rod cup 74 drops together with push rod 76. Spring loaded yoke 40, bearing downwardly on projection 70, forces the rocker arm 64 to follow the push rod 76 so closely that substantial separation of the uppermost end of the push rod and the rocker arm does not occur. The valve 84 is subsequently closed by a double compression spring 88.

Referring to FIGURES 68, there may be seen an alternative form of a rocker arm spring 90. Included in rocker arm spring 90 is a pair of spaced, axially aligned coils 92 and 94, each of which has an internal leg 96 and 98, respectively. The configuration of internal legs 96 and 98 is substantially identical to external legs 20 and 22 of the first form of the invention, and said legs 96 and 98 are devoted to the same purpose as said legs 20 and 22, and function in substantially the same manner. However, the axis of axially aligned loops 104 and 106 on legs 96 and 98 respectively, is offset with respect to a vertical plane passing through the axis of coils 92 and 94.

External legs 100 and 102 are connected together by a yoke 108, but said legs 100 and 102 extend in a direction generally opposed to the direction of extension of legs 16 and 18 in the first form of the invention, so that, instead of yoke 109 bearing down on rocker arm 64, yoke 108 bears up on the rocker arm in a manner hereinafter described.

Legs 96 and 98 are generally parallel to a vertical plane passing through the axis of the coils 92 and 94, whereas, legs 100 and 102 again form an acute angle with the vertical plane.

When rocker arm spring 90 is secured to shaft 52 (see FIGURES 6 and 7), yoke 108 is located on the underside of rocker arm 64 adjacent the anvil 80, and the torque exerted by rocker arm spring 90 to force the rocker arm to follow push rod 76 is upwardly directed, as represented by the torque arrow shown in FIGURE 7. Although yoke 108 is located on the underside of the rocker arm 64,

the results achieved are substantially the same as those achieved by using rocker arm spring 10.

While the instant invention has been shown and described herein in what is conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein, but it is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

What is claimed is:

1. In combination, an internal combustion engine, a rocker arm, a rocker arm actuating rod, and a spring for torque biasing the rocker arm into substantially continuous engagement with the actuating rod, which comprises:

(a) an internal combustion engine;

(b) a rocker arm;

(c) a split shaft comprising a pair of substantially semicylindrical portions;

(d) a movable rod mounted on said engine and adapted to actuate said rocker arm;

(e) a spring having a pair of parallel coils spaced apart from each other and adapted to produce a torque;

(f) a first leg on each of said coils, each of said first legs having a semi-circular loop disposed so as to surround one semi-cylindrical portion of said split shaft;

(g) a finger on each of said coils, each of said fingers being disposed so as to substantially close its adjacent loop, and said fingers being diametrically seated between the fiat surfaces of the semi-cylindrical portions of said shaft;

(11) a second leg on each of said coils; and

(i) a yoke interconnecting said second legs, said yoke being in torque biasing engagement with said rocker arm so as to cause said rocker arm to follow said movable rod.

2. The combination as defined in claim 1, wherein one of said semi-cylindrical portions of the shaft has channels therein, and wherein said fingers are seated in said channels.

3. The combination as defined in claim 1, wherein said second legs have a plurality of bends formed therein so as to foreshorten said second legs and render them substantially rigid.

References Cited in the file of this patent UNITED STATES PATENTS 227,609 Brown May 18, 1880 1,270,941 Goodwin July 2, 1918 1,363,060 Shearer Dec. 21, 1920 1,400,253 Wicker Dec. 13, 1921 1,728,149 Berne Sept. 10, 1929 1,979,348 Russell Nov. 6, 1934 2,824,554 Sampietro Feb. 25, 1958 FOREIGN PATENTS 875,350 Great Britain Aug. 16, 1961 

1. IN COMBINATION, AN INTERNAL COMBUSTION ENGINE, A ROCKER ARM, A ROCKER ARM ACTUATING ROD, AND A SPRING FOR TORQUE BIASING THE ROCKER ARM INTO SUBSTANTIALLY CONTINUOUS ENGAGEMENT WITH THE ACTUATING ROD, WHICH COMPRISES: (A) AN INTERNAL COMBUSTION ENGINE; (B) A ROCKER ARM; (C) A SPLIT SHAFT COMPRISING A PAIR OF SUBSTANTIALLY SEMICYLINDRICAL PORTIONS; (D) A MOVABLE ROD MOUNTED ON SAID ENGINE AND ADAPTED TO ACTUATE SAID ROCKER ARM; (E) A SPRING HAVING A PAIR OF PARALLEL COILS SPACED APART FROM EACH OTHER AND ADAPTED TO PRODUCE A TORQUE; (F) A FIRST LEG ON EACH OF SAID COILS, EACH OF SAID FIRST LEGS HAVING A SEMI-CIRCULAR LOOP DISPOSED SO AS TO SURROUND ONE SEMI-CYLINDRICAL PORTION OF SAID SPLIT SHAFT; (G) A FINGER ON EACH OF SAID COILS, EACH OF SAID FINGERS BEING DISPOSED SO AS TO SUBSTANTIALLY CLOSE ITS ADJACENT LOOP, AND SAID FINGERS BEING DIAMETRICALLY SEATED BETWEEN THE FLAT SURFACES OF THE SEMI-CYLINDRICAL PORTIONS OF SAID SHAFT; (H) A SECOND LEG ON EACH OF SAID COILS; AND (I) A YOKE INTERCONNECTING SAID SECOND LEGS, SAID YOKE BEING IN TORQUE BIASING ENGAGEMENT WITH SAID ROCKER ARM SO AS TO CAUSE SAID ROCKER ARM TO FOLLOW SAID MOVABLE ROD. 